泥水盾构中泥浆劈裂地层的影响因素分析

Investigation of Influencing Factors on Slurry Fracturing during Tunnel Shield

鉴于泥水盾构技术中泥浆压力的合理控制能有效防止泥浆劈裂现象的发生,通过自制的泥浆劈裂装置和常规三轴仪模拟了泥浆劈裂地层的过程,研究了泥浆粘度、泥浆密度和地层围压对泥浆劈裂压力的影响。结果表明,当泥浆粘度在25~35s之间时,劈裂压力随粘度的增大呈近似线性增大,但超过该范围后,劈裂压力随粘度的继续增大而变化较小;当围压由50kPa增大至200kPa时,劈裂压力亦显著提高,但泥浆密度的影响则相对较小;通过与理论计算结果的对比,进一步验证了试验数据的可靠性,为泥浆压力的优化设计提供了参考依据。

Reasonable control of slurry pressure can effectively prevent slurry fracturing during tunnel shield. In this paper, a homemade test instrument and common triaxial apparatus in laboratory were used to simulate the process of slurry fracturing. The impacts of slurry viscosity, slurry density and confining pressure on fracturing pressure were in- vestigated. It was found that fracturing pressure increased linearly with increasing slurry viscosity ranging from 25 s to 35 s, whereas the effect was insignificant when the slurry viscosity was larger than the range; the fracturing pressure in- creased significantly when confining pressure varied from 50 kPa to 200 kPa. However, the effect of slurry density was very limited. In addition, comparison of theoretical results verifies the reliability of test results. Thus, these studies can contribute to the optimal design of slurry pressure.